HEMT transistors (High Electron Mobility Transistors) made of III-N semiconductor materials are conventionally “normally on,” i.e., they have a negative threshold voltage and can conduct current with a voltage between the gate and the source of 0V. These components with negative threshold voltages are called depletion mode (or “D-Mode”) components.
It is preferable for power electronics applications to have so-called “normally off” components, i.e., to have a positive threshold voltage that, therefore, cannot conduct current when the gate voltage is 0V. These components are currently called enhancement mode (“E-mode”) components.
Manufacturing such high-voltage components on III-N E-mode semiconductor materials proved to be complex and these components often have lower intrinsic performances than similar D-mode components.
An alternative to a simple high-voltage E-mode component is to combine a high-voltage D-mode component, such as a D-mode HEMT transistor made of III-N semiconductor materials, with a low-voltage E-mode component, such as an E-Mode MOSFET (Metal Oxide Semiconductor Field Effect Transistor) made of silicon. Two chips 1, 2, respectively comprising the HEMT and MOSFET components, are then associated to form a hybrid integrated circuit 3, for example, a switch integrated circuit.
FIG. 1a shows the block diagram of a hybrid, so-called “cascode,” circuit associating HEMT and MOSFET components. An integrated circuit 3 implementing this first configuration is shown in FIG. 1b. The drain 21 and the source 22 of an E-mode MOSFET chip 2 are, respectively, connected to the source 12 and the gate 13 of a D-mode HEMT chip 1. This electrical connection is provided in the housing 4 of the integrated circuit 3 comprising two chips 1, 2, usually through a “wire bonding” 5 between the gate bump contacts 13, 23, the source bump contacts 12, 22 and the drain bump contacts 11, 21 accessible on each of the chips 1, 2. In the integrated cascode circuit 3, the gate 23 of the MOSFET chip 2 controls the setting of the ON mode or the OFF mode of the integrated circuit 3.
The gate bump contact 23 of the MOSFET chip 2 is connected in the housing 4 of the integrated circuit 3 to a gate pin 33. The source bump contact 22 of the MOSFET chip 2 is connected in the housing 4 to a source pin 32. Eventually, the drain bump contact of the HEMT chip 1 is connected, still in the housing 4, to a drain pin 31. The three pins 31, 32, 33 provide the electrical connections of the integrated circuit 3 outside the housing 4.
FIG. 1c shows the block diagram of a so-called “dual” hybrid circuit associating HEMT and MOSFET components. An integrated circuit 3 implementing this second configuration is shown in FIG. 1d. According to this alternative configuration, the chips 1, 2, respectively comprising the HEMT and MOSFET components, are simply connected in series, with the drain 21 of the E-mode MOSFET chip 2 being connected to the source 12 of the D-mode HEMT chip 1. In this configuration, the housing 4 of the integrated circuit 3 has an additional gate pin 34 electrically connected to the gate bump contact 13 of the D-mode HEMT chip 1 so as to enable the direct control of this transistor.
For a more detailed discussion of the operating principles of a “cascode” circuit or a “dual” circuit, reference can be made to the document “A Dual-Mode Driver IC with Monolithic Negative Drive-Voltage Capability and Digital Current-Mode Controller for Depletion-Mode GaN HEMT,” by Yue Wen et al., IEEE Transactions on Power Electronics, Issue 99, 1996.
Whatever the chosen configuration, the integrated circuit 3 is intended to be positioned on a printed circuit board to be interconnected with other components.
As is well known per se, for instance, from documents U.S. Pat. Nos. 92,683,512 or 8,624,662, it is customary to include additional components, such as resistors or capacitances, in the integrated circuit 3 to form a protective device. This protection device aims at controlling, especially during the switching transient phases, the voltage (or current) that may flow (or circulate) in some nodes of the hybrid circuit.
The nature of the protective device may depend on the considered application (for instance, the considered switching frequency, or the amplitude of the voltage to be switched, etc.), or on the nature of the other components that the integrated circuit 3 can be connected with on the PCB.
Integrated circuits of the prior art implementing a hybrid circuit do not make it possible to adjust the protection device configuration previously planned by the manufacturer.
Besides, having an integrated circuit comprising a high-voltage E-mode component and a low-voltage D-mode component, which could be used, as needed, in a “cascode” configuration or in a “dual” configuration, might be desirable.
More generally, today, no integrated circuit exists for applications in the field of power switching, comprising an high-voltage E-mode component and a low-voltage D-mode component, with a versatile, simple and robust composition, i.e., which can be used in a wide range of applications (with highly variable switching currents, voltages and frequencies) and (specifically thermal or electromagnetic) environments without changing the internal architecture thereof.